Masts are being erected in step with the existing line
The 340-kilometre-long 380-kilovolt Ultranet line will be able to transmit around 2,000 megawatts of electrical power. It uses existing lines as much as possible. The conversion to direct current operation is carried out by installing suitable insulators. Therefore, only 4 masts need to be newly erected between Ried and Bürstadt-Ost in Hesse. However, in the further course to Mannheim-Wallstadt, a replacement construction is necessary on the existing route for 18.9 kilometres. For this purpose, an existing 220-kV line will be dismantled. The new masts, which will be on average 58 m high, will be erected as closely as possible to the masts of an existing 380-kV line running parallel to them.
Bored piles transfer high loads into deeper, more stable soil layers
For the deep foundations of 31 masts, the PORR special civil engineering team constructed 124 large-diameter piles with a diameter of 1200 mm; 5 masts are founded on 20 large-diameter piles with a diameter of 1500 mm. Due to construction time constraints, as well as the overarching overhead line planning, the locations could not be processed in any order.
The construction of site roads and the logistics to and from the construction site repeatedly presented challenges for all project participants at the Lampertheim, Viernheim, Wallstadt and Mannheim sites. Space was limited and the ground lacked sufficient load-bearing capacity, making the heavy transport of drilling equipment from site to site a particularly demanding task.
André Schürmann, the branch manager, is extremely satisfied with how the project has gone: ‘The Ultranet project is fully in line with our “Green and Lean” strategy.’ One of the main areas of focus was on the surrounding soil, which could not be contaminated. Bio-oil was used in the hydraulic hoses to avoid contaminating the groundwater. In line with the Lean methodology, all workflows were discussed in detail with the team and flexibly adapted to the local conditions as needed. Close coordination with an external expert from the client Amprion and the trusting relationship with our client contributed to a timely and high-quality execution.’
